From: Andy Lutomirski <luto@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
LKML <linux-kernel@vger.kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
Arnd Bergmann <arnd@arndb.de>, Anton Blanchard <anton@ozlabs.org>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH v3 2/4] membarrier: Add an actual barrier before rseq_preempt()
Date: Tue, 8 Dec 2020 20:12:06 -0800 [thread overview]
Message-ID: <CALCETrWPLcNk5XsartvjPD+LNxrmwHrv5hY4hrFwbhYjugw+9g@mail.gmail.com> (raw)
In-Reply-To: <d3e7197e034fa4852afcf370ca49c30496e58e40.1607058304.git.luto@kernel.org>
On Thu, Dec 3, 2020 at 9:07 PM Andy Lutomirski <luto@kernel.org> wrote:
>
> It seems to me that most RSEQ membarrier users will expect any
> stores done before the membarrier() syscall to be visible to the
> target task(s). While this is extremely likely to be true in
> practice, nothing actually guarantees it by a strict reading of the
> x86 manuals. Rather than providing this guarantee by accident and
> potentially causing a problem down the road, just add an explicit
> barrier.
>
> Cc: stable@vger.kernel.org
Fixes: 2a36ab717e8f ("rseq/membarrier: Add
MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ")
which is new in 5.10, so it doesn't need cc:stable if it makes 5.10.
next prev parent reply other threads:[~2020-12-09 4:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 5:07 [PATCH v3 0/4] membarrier fixes Andy Lutomirski
2020-12-04 5:07 ` [PATCH v3 1/4] x86/membarrier: Get rid of a dubious optimization Andy Lutomirski
2020-12-09 4:10 ` Andy Lutomirski
2020-12-09 8:42 ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2020-12-04 5:07 ` [PATCH v3 2/4] membarrier: Add an actual barrier before rseq_preempt() Andy Lutomirski
2020-12-09 4:12 ` Andy Lutomirski [this message]
2020-12-09 8:42 ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2020-12-14 18:05 ` Andy Lutomirski
2020-12-04 5:07 ` [PATCH v3 3/4] membarrier: Explicitly sync remote cores when SYNC_CORE is requested Andy Lutomirski
2020-12-09 4:13 ` Andy Lutomirski
2020-12-09 8:42 ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2020-12-04 5:07 ` [PATCH v3 4/4] membarrier: Execute SYNC_CORE on the calling thread Andy Lutomirski
2020-12-04 19:35 ` Mathieu Desnoyers
2020-12-09 4:15 ` Andy Lutomirski
2020-12-09 8:42 ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
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